ON Semiconductor announced a monolithic analog Integrated Circuit (IC) containing a precision 2.6 volt voltage reference and two operational amplifiers, to address the accurate control of output voltage and current requirement by providing accurate current and voltage control of power supplies and battery chargers.

ON Semiconductor designed the NCP4300A for cost sensitive applications such as charger adaptors, notebook PC adaptors and power supplies.

Typical feedback-loop circuits may consist of a voltage and current amplifier, summing circuitry and a reference. The NCP4300A contains all of these functions and is easily configurable into an analog regulation control circuit that will simultaneously close the voltage and current feedback with minimal external components. It will control the feedback loop in either constant-voltage (CV) or constant-current (CC) mode with precise, smooth crossover.

A simple solution to reducing the costs of a charger in the appliance market -- like laptop chargers -- this part provides the essential circuitry for both voltage and current control of the charging process. On one of the on-chip op amps a 2.6-V reference is a constant connection. The other input is for the voltage sensing; on a second op amp the inputs are left uncommitted so that it can be configured for current control.

With the first amplifier, as the threshold is internally connected to the reference, the voltage regulation threshold is fixed at 2.6 V; higher cell voltages can be regulated using external potential dividers. The second op amp monitors the voltage that is across a small ohmic sense resistor. The reference precision over temperature is 1% and the part has a 80 uA to 80 mA sink current range. With a 5-V supply (it can go from 3.0 to 35 V) each op amp has a quiescent current of 210 uA.